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Title: Field-Scale Assessment of Desiccation Implementation for Deep Vadose Zone Contaminants

Abstract

Desiccation of the vadose zone has the potential to reduce the flux of contaminants to underlying groundwater by removing moisture and decreasing the aqueous-phase permeability of the desiccated zone. However, data to evaluate implementation of desiccation are needed to enable consideration of desiccation as a potential remedy. Implementation of desiccation was field tested by injecting dry nitrogen gas to a target treatment zone and monitoring the spatial and temporal progress of the drying process. Aqueous waste discharges to disposal cribs approximately 50 years ago distributed water and contaminants, including primarily technetium-99 and nitrate, within the 100-m deep vadose zone at the test site. A field test location was selected adjacent to one of the former disposal cribs. The test was conducted in a contaminated portion of the vadose zone dominated by fine sands with lenses of silt material. Desiccation reduced volumetric moisture content to as low as 0.01. The lateral and vertical distribution of drying from the injection well was influenced by the subsurface heterogeneity. However, over time, desiccation occurred in the initially wetter, lower permeability lenses.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1057831
Report Number(s):
PNNL-SA-83775
42793; 830403000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Vadose Zone Journal, 11(4)
Additional Journal Information:
Journal Name: Vadose Zone Journal, 11(4)
Country of Publication:
United States
Language:
English
Subject:
vadose zone; remediation; Environmental Molecular Sciences Laboratory

Citation Formats

Truex, Michael J., Oostrom, Martinus, Strickland, Christopher E., Chronister, Glen B., Benecke, Mark W., and Johnson, Christian D. Field-Scale Assessment of Desiccation Implementation for Deep Vadose Zone Contaminants. United States: N. p., 2012. Web. doi:10.2136/vzj2011.0144.
Truex, Michael J., Oostrom, Martinus, Strickland, Christopher E., Chronister, Glen B., Benecke, Mark W., & Johnson, Christian D. Field-Scale Assessment of Desiccation Implementation for Deep Vadose Zone Contaminants. United States. doi:10.2136/vzj2011.0144.
Truex, Michael J., Oostrom, Martinus, Strickland, Christopher E., Chronister, Glen B., Benecke, Mark W., and Johnson, Christian D. Thu . "Field-Scale Assessment of Desiccation Implementation for Deep Vadose Zone Contaminants". United States. doi:10.2136/vzj2011.0144.
@article{osti_1057831,
title = {Field-Scale Assessment of Desiccation Implementation for Deep Vadose Zone Contaminants},
author = {Truex, Michael J. and Oostrom, Martinus and Strickland, Christopher E. and Chronister, Glen B. and Benecke, Mark W. and Johnson, Christian D.},
abstractNote = {Desiccation of the vadose zone has the potential to reduce the flux of contaminants to underlying groundwater by removing moisture and decreasing the aqueous-phase permeability of the desiccated zone. However, data to evaluate implementation of desiccation are needed to enable consideration of desiccation as a potential remedy. Implementation of desiccation was field tested by injecting dry nitrogen gas to a target treatment zone and monitoring the spatial and temporal progress of the drying process. Aqueous waste discharges to disposal cribs approximately 50 years ago distributed water and contaminants, including primarily technetium-99 and nitrate, within the 100-m deep vadose zone at the test site. A field test location was selected adjacent to one of the former disposal cribs. The test was conducted in a contaminated portion of the vadose zone dominated by fine sands with lenses of silt material. Desiccation reduced volumetric moisture content to as low as 0.01. The lateral and vertical distribution of drying from the injection well was influenced by the subsurface heterogeneity. However, over time, desiccation occurred in the initially wetter, lower permeability lenses.},
doi = {10.2136/vzj2011.0144},
journal = {Vadose Zone Journal, 11(4)},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {11}
}